The Chemistry of the Defensive Secretions of Three Species of Millipedes in the Genus Brachycybe.

Millipedes have long been known to produce a diverse array of chemical defense agents that deter predation. These compounds, or their precursors, are stored in high concentration within glands (ozadenes) and are released upon disturbance. The subterclass Colobognatha contains four orders of millipedes, all of which are known to produce terpenoid alkaloids-spare the Siphonophorida that produce terpenes. Although these compounds represent some of the most structurally-intriguing millipede-derived natural products, they are the least studied class of millipede defensive secretions. Here, we describe the chemistry of millipede defensive secretions from three species of Brachycybe: Brachycybe producta, Brachycybe petasata, and Brachycybe rosea. Chemical investigations using mass spectrometry-based metabolomics, chemical synthesis, and 2D NMR led to the identification of five alkaloids, three of which are new to the literature. All identified compounds are monoterpene alkaloids with the new compounds representing indolizidine (i.e. hydrogosodesmine) and quinolizidine alkaloids (i.e. homogosodesmine and homo-hydrogosodesmine). The chemical diversity of these compounds tracks the known species phylogeny of this genus, rather than the geographical proximity of the species. The indolizidines and quinolizidines are produced by non-sympatric sister species, B. producta and B. petasata, while deoxybuzonamine is produced by another set of non-sympatric sister species, B. rosea and Brachycybe lecontii. The fidelity between the chemical diversity and phylogeny strongly suggests that millipedes generate these complex defensive agents de novo and begins to provide insights into the evolution of their biochemical pathways.

A new species of Illacme from southern California (Siphonophorida, Siphonorhinidae).

The millipede fauna inhabiting deep soil are poorly known. They are small and threadlike, slow moving, lacking pigmentation, and rarely encountered due to their obscure underground way of life. One family, the Siphonorhinidae, encompasses four genera and 12 species in a fragmentary distribution in California, southern Africa, Madagascar, the Malay Archipelago, and Indo-Burma. The family is represented in the Western Hemisphere by a single genus, Illacme Cook & Loomis, 1928 from California, with its closest known relative, Nematozoniumfilum Verhoeff, 1939, from southern Africa. A new species of this family is documented from soil microhabitats in the Los Angeles metropolitan area, Illacmesocal Marek & Shear, sp. nov. Based on this discovery and the recent documentation of other endogean millipede species, we show that these grossly understudied subterranean fauna represent the next frontier of discovery. However, they are threatened by encroaching human settlement and habitat loss, and conservation of this species and other subterranean fauna is of high importance.

The millipede family Striariidae Bollman, 1893. VIII. Three new genera and four new species of minute millipedes from Oregon and Washington, USA(Diplopoda, Chordeumatida, Striarioidea).

We describe three new genera and four new species of small, litter-dwelling millipedes from the states of Oregon and Washington, USA: Miniaria ramifera, n. gen., n. sp., Miniaria richarti, n. gen., n. sp., Tigraria oregonensis, n. gen., n. sp., and Kingaria prattensis, n. gen., n. sp. Some of the unusual characters of these species are discussed, including a new type of sensory array on the third tarsus of males and a newly observed mandibular gland.

Reconsidering tympanal-acoustic interactions leads to an improved model of auditory acuity in a parasitoid fly.

Although most binaural organisms locate sound sources using neurological structures to amplify the sounds they hear, some animals use mechanically coupled hearing organs instead. One of these animals, the parasitoid flyOrmia ochracea(O. ochracea), has astoundingly accurate sound localization abilities. It can locate objects in the azimuthal plane with a precision of 2°, equal to that of humans, despite an intertympanal distance of only 0.5 mm, which is less than1/100th of the wavelength of the sound emitted by the crickets that it parasitizes.O. ochraceaaccomplishes this feat via mechanically coupled tympana that interact with incoming acoustic pressure waves to amplify differences in the signals received at the two ears. In 1995, Mileset aldeveloped a model of hearing mechanics inO. ochraceathat represents the tympana as flat, front-facing prosternal membranes, though they lie on a convex surface at an angle from the flies' frontal and transverse planes. The model works well for incoming sound angles less than±30∘but suffers from reduced accuracy (up to 60% error) at higher angles compared to response data acquired fromO. ochraceaspecimens. Despite this limitation, it has been the basis for bio-inspired microphone designs for decades. Here, we present critical improvements to this classic hearing model based on information from three-dimensional reconstructions ofO. ochracea's tympanal organ. We identified the orientation of the tympana with respect to a frontal plane and the azimuthal angle segment between the tympana as morphological features essential to the flies' auditory acuity, and hypothesized a differentiated mechanical response to incoming sound on the ipsi- and contralateral sides that depend on these features. We incorporated spatially-varying model coefficients representing this asymmetric response, making a new quasi-two-dimensional (q2D) model. The q2D model has high accuracy (average errors of under 10%) for all incoming sound angles. This improved biomechanical model may inform the design of new microscale directional microphones and other small-scale acoustic sensor systems.

Myriapods.

Paul Marek and William Shear introduce the arthropod sub-phylum myriapoda, which includes centipedes, millipedes and other multi-legged animals.

A revision of the wilsoni species group in the millipede genus Nannaria Chamberlin, 1918 (Diplopoda, Polydesmida, Xystodesmidae).

Although many new species of the millipede genus Nannaria Chamberlin, 1918 have been known from museum collections for over half a century, a systematic revision has not been undertaken until recently. There are two species groups in the genus: the minor species group and the wilsoni species group. In this study, the wilsoni species group was investigated. Specimens were collected from throughout its distribution in the Appalachian Mountains of the eastern United States and used for a multi-gene molecular phylogeny. The phylogenetic tree recovered Nannaria and the two species groups as monophyletic, with Oenomaeapulchella as its sister group. Seventeen new species were described, bringing the composition of the wilsoni species group to 24 species, more than tripling its known diversity, and increasing the total number of described Nannaria species to 78. The genus now has the greatest number of species in the family Xystodesmidae. Museum holdings of Nannaria were catalogued, and a total of 1,835 records used to produce a distribution map of the species group. Live photographs, illustrations of diagnostic characters, ecological notes, and conservation statuses are given. The wilsoni species group is restricted to the Appalachian region, unlike the widely-distributed minor species group (known throughout eastern North America), and has a distinct gap in its distribution in northeastern Tennessee and adjacent northwestern North Carolina. The wilsoni species group seems to be adapted to mesic microhabitats in middle to high elevation forests in eastern North America. New species are expected to be discovered in the southern Appalachian Mountains.

The millipede family Striariidae Bollman, 1893. IV. Amplaria oedipus, n. sp., with a secondary sexual modification of males unique among millipedes (Diplopoda, Chordeumatida, Striarioidea).

A new species, Amplaria oedipus, is described from Oregon, USA. Males of the new species have greatly inflated pyriform tarsi on the 5th and 6th legpairs, which is a secondary sexual modification previously not known from any other millipede.

The milliped family Striariidae Bollman, 1893. V. Stegostriaria dulcidormus, n. gen., n. sp., Kentrostriaria ohara, n. gen., n. sp., and the convergent evolution of exaggerated metazonital crests (Diplopoda, Chordeumatida, Striarioidea).

Two new genera and species, Stegostriaria dulcidormus (Trisariinae) and Kentrostriaria ohara (Striariinae), are described from Oregon and Idaho, respectively. The new species are distinct from any other striariids, and indeed from any other chordeumatidan millipedes, in having the second dorsal crests greatly enlarged, giving them a fanciful resemblance to stegosaurid dinosaurs. In spite of this similarity, the two species are so distinct they cannot be accommodated in the same genus or the same subfamily. The exaggerated metazonital crests are therefore attributed to convergent evolution. We present a key to the genera of the family Striariidae.

Deoxybuzonamine Isomers from the Millipede Brachycybe lecontii (Platydesmida: Andrognathidae).

Millipedes (Diplopoda) are well known for their toxic or repellent defensive secretions. Here, we describe (6aR,10aS,10bR)-8,8-dimethyldodecahydropyrrolo[2,1-a]isoquinoline [trans-anti-trans-deoxybuzonamine (1a)] and (rel-6aR,10aR,10bR)-8,8-dimethyldodecahydropyrrolo[2,1-a]isoquinoline [trans-syn-cis-deoxybuzonamine (1b)], two isomers of deoxybuzonamine found in the chemical defense secretions of the millipede Brachycybe lecontii Wood (Colobognatha, Platydesmida, Andrognathidae). The carbon-nitrogen skeleton of these compounds was determined from their MS and GC-FTIR spectra obtained from the MeOH extract of whole millipedes, along with a subsequent selective synthesis. Their structures were established from their 1D (1H, 13C) and 2D NMR (COSY, NOESY, multiplicity-edited HSQC, HSQC-TOCSY, HMBC) spectra. Additionally, computational chemistry (DFT and DP4) was used to identify the relative configurations of 1a and 1b by comparing predicted 13C data to their experimental values, and the absolute configuration of 1a was determined by comparing its experimental specific rotation with that of the computationally calculated value. This is the first report of dodecahydropyrrolo[2,1-a]isoquinoline alkaloids from a platydesmidan millipede.

Phylogenetic review of the millipede genus Cherokia Chamberlin, 1949 (Polydesmida, Xystodesmidae).

The millipede genus Cherokia Chamberlin, 1949 is a monospecific taxon, with the type species Cherokiageorgiana (Bollman, 1889). The last revision of the genus was made by Hoffman (1960) where he established three subspecies. Here we used molecular phylogenetics to assess the genus and evaluate whether it is a monophyletic group, and if the subspecies are each monophyletic. We included material from literature records and three natural history collections. Newly collected samples were obtained through a citizen science project. Morphological characters underlying subspecies groups-the shape of the paranota, body size, and coloration-were evaluated. A molecular phylogeny of the genus was estimated based on DNA sequences for seven gene loci, and a species delimitation analysis was used to evaluate the status of the subspecies. The documented geographical range of Cherokia in the United States was expanded to include a newly reported state record (Virginia) and about 160 new localities compared to the previously known range. Morphological characters, which included the shape of the paranota and body size that had been historically used to establish subspecies, showed clinal variation with a direct relationship with geographical distribution and elevation, but not with phylogeny. Coloration was highly variable and did not accord with geography or phylogeny. The phylogeny recovered Cherokia as a monophyletic lineage, and the species delimitation test supported the existence of a single species. The subspecies Cherokiageorgianaducilla (Chamberlin, 1939) and Cherokiageorgianalatassa Hoffman, 1960 have been synonymized with Cherokiageorgiana. The molecular and morphological evidence showed that Cherokia is a monospecific genus with the sole species, Cherokiageorgiana, being geographically widespread and highly variable in its morphology.

The millipede family Striariidae Bollman, 1893. VII. Petra sierwaldae, n. gen., n. sp., a minute millipede from Idaho, USA (Diplopoda, Chordeumatida, Striariidae).

Petra sierwaldae, n. gen., n. sp. is described from males and females collected at four localities in Kootenai County, Idaho, USA. The new genus is defined by its unique gonopod and ninth leg anatomy, a notched collum and single ommatidium on each side of the head, and lacking third coxal flasks as well as having modified fifth coxae.

The millipede family Striariidae Bollman, 1893. VI. Six new genera and thirteen new species from western North America (Diplopoda, Chordeumatida, Striarioidea).

The following new genera and species of Striariidae are described from the states of California, Oregon and Washington: Nototrisaria ornata n. gen., n. sp., Maraplia napa n. gen., n. sp., Maraplia chico n. gen., n. sp., Maraplia schusteri n. gen., n. sp., Lamparia curryensis n. gen., n. sp., Lamparia bentonensis n. gen., n. sp., Lamparia pratensis n. gen., n. sp., Lamparia millicoma n. gen., n. sp., Rampalia cheathamensis n. gen., n. sp., Plaramia arcata n. gen., n. sp., Plaramia johnsonae n. gen., n. sp., Ralampia complexa n. gen., n. sp., and Ralampia filamentosa n. gen., n. sp.. The new species are all very small millipedes, 5.5 mm or less in length and with two or three ommatidia on each side of the head or blind. The majority have the sixth metazonital crest larger than the other crests and extended horizontally, so that the animals have the general appearance of having paranota. A new key to striariid genera is presented.

The first true millipede-1306 legs long.

The name "millipede" translates to a thousand feet (from mille "thousand" and pes "foot"). However, no millipede has ever been described with more than 750 legs. We discovered a new record-setting species of millipede with 1,306 legs, Eumillipes persephone, from Western Australia. This diminutive animal (0.95 mm wide, 95.7 mm long) has 330 segments, a cone-shaped head with enormous antennae, and a beak for feeding. A distant relative of the previous record holder, Illacme plenipes from California, it belongs to a different order, the Polyzoniida. Discovered 60 m below ground in a drill hole created for mineral exploration, E. persephone possesses troglomorphic features; it lacks eyes and pigmentation, and it has a greatly elongated body-features that stand in stark contrast to its closest surface-dwelling relatives in Australia and all other members of its order. Using phylogenomics, we found that super-elongation (> 180 segments) evolved repeatedly in the millipede class Diplopoda. The striking morphological similarity between E. persephone and I. plenipes is a result of convergent evolution, probably for locomotion in similar soil habitats. Discovered in the resource-rich Goldfields-Esperance region and threatened by encroaching surface mining, documentation of this species and conservation of its habitat are of critical importance.

Three new genera and eighteen new species of miniature polydesmid millipedes from the northwestern United States (Diplopoda, Polydesmida, Polydesmidae).

Three new genera, Retrorsioides, Rowlandesmus and Benedictesmus, are described and the polydesmid millipede fauna of North America is briefly reviewed with an emphasis on the genera Bidentogon Buckett Gardner, 1968 and Retrorsia Shelley, 2003. Eighteen new species are described: Bidentogon buttensis, Bidentogon norcal, Retrorsia leonardi, Retrorsia benedictae, Retrorsia richarti, Retrorsia gracilis, Retrorsia simplicissima, Retrorsioides castellum, Retrorsioides linnensis, Retrorsioides kittitas, Retrorsioides bammerti, Retrorsioides arboramagna, Rowlandesmus millicoma, Rowlandesmus dentogonopus, Benedictesmus aureua, Benedictesmus ellenae, Benedictesmus yaquina and Benedictesmus timber. Natural history notes and illustrations are provided of putative commensal fungi, nematodes and a mite found on the millipede specimens.

A revision of the minor species group in the millipede genus Nannaria Chamberlin, 1918 (Diplopoda, Polydesmida, Xystodesmidae).

Millipedes in the family Xystodesmidae (Polydesmida) are often referred to as "colorful, flat-backed millipedes" for their bright aposematic coloration and tendency to form Müllerian mimicry rings in the Appalachian region. However, there are many species of Xystodesmidae that do not display colorful warning patterns, and instead have more cryptic appearances. Perhaps for this reason, groups such as the genus Nannaria have remained understudied, despite containing a large number of undescribed species. Before his death in 2012, R. L. Hoffman worked on a revision of the genus Nannaria, and synthesized material and drawings since 1949. Here the work is continued, inferring a molecular phylogeny of the Nannariini (Nannaria + Oenomaea pulchella), and revealing two clades within the genus. One clade is named the minor species group, and the second is the wilsoni species group. This revision, using a molecular phylogenetic framework, is the basis for descriptions of 35 new species in the minor species group. A multi-gene molecular phylogeny is used to make taxonomic changes in the taxon. Eleven putative species of Nannaria are also illustrated and discussed. Additionally, detailed collection, natural history and habitat notes, distribution maps, and a key to species of the Nannaria minor species group are provided. These items are synthesized as a basis for a revision of the genus, which hopefully will aid conservation and evolutionary investigations of this cryptic and understudied group.

Natural history of the social millipede Brachycybe lecontii Wood, 1864.

The millipede Brachycybe lecontii Wood, 1864 is a fungivorous social millipede known for paternal care of eggs and forming multi-generational aggregations. We investigated the life history, paternal care, chemical defence, feeding and social behaviour of B. lecontii and provided morphological and anatomical descriptions, using light and scanning electron microscopy. Based on observations of B. lecontii from 13 locations throughout its distribution, we report the following natural history aspects. The oviposition period of B. lecontii lasted from mid-April to late June and the incubation period lasted 3-4 weeks. Only males cared for the eggs and subsequent care of juveniles was not observed. In one case, the clutches of two males became combined and they were later cared for by only one of the males. The defensive compound of B. lecontii is stored in large glands occupying a third of the paranotal volume and were observed only in stadia II millipedes and older. We observed B. lecontii feeding on fungi of the order Polyporales and describe a cuticular structure on the tip of the labrum that may relate to fungivory. We found that their stellate-shaped aggregations (pinwheels) do not form in the absence of fungus and suggest the aggregation is associated with feeding. We describe and illustrate a previously undescribed comb-like structure on the tibia and tarsi of the six anterior-most leg-pairs and measure the colour and spectral reflectance of the B. lecontii exoskeleton.

Structure and pigment make the eyed elater's eyespots black.

Surface structures that trap light leading to near complete structural absorption creates an appearance of "super black." Well known in the natural world from bird feathers and butterfly scales, super black has evolved independently from various anatomical structures. Due to an exceptional ability to reduce specular reflection, these biological materials have garnered interest from optical industries. Here we describe the false eyes of the eyed elater click beetle, which, while not classified as super black, still attains near complete absorption of light partly due to an array of vertically-aligned microtubules. These cone-shaped microtubules are modified hairs (setae) that are localized to eyespots on the dorsum of the beetle, and absorb 96.1% of incident light (at a 24.8° collection angle) in the spectrum between 300-700 nm. Filled with melanin, the setae combine structure and pigment to generate multiple reflections and refractions causing light to travel a greater distance. This light-capturing architecture leaves little light available to receivers and the false eyes appear as deep black making them appear more conspicuous to predators.

Diversity and function of fungi associated with the fungivorous millipede, Brachycybe lecontii.

Fungivorous millipedes (subterclass Colobognatha) likely represent some of the earliest known mycophagous terrestrial arthropods, yet their fungal partners remain elusive. Here we describe relationships between fungi and the fungivorous millipede, Brachycybe lecontii. Their fungal community is surprisingly diverse, including 176 genera, 39 orders, four phyla, and several undescribed species. Of particular interest are twelve genera conserved across wood substrates and millipede clades that comprise the core fungal community of B. lecontii. Wood decay fungi, long speculated to serve as the primary food source for Brachycybe species, were absent from this core assemblage and proved lethal to millipedes in pathogenicity assays while entomopathogenic Hypocreales were more common in the core but had little effect on millipede health. This study represents the first survey of fungal communities associated with any colobognath millipede, and these results offer a glimpse into the complexity of millipede fungal communities.

Urochordeumatidae Silvestri, 1909, a millipede family endemic to Washington State, USA (Chordeumatida, Striariidea, Striarioidea).

Urochordeumatidae Silvestri, 1909 includes a single species, Urochordeuma bumpusi Silvestri, 1909, with U. porona Chamberlin, 1941 as a new junior subjective synonym. The family Urochordeumatidae is removed from the superfamily Caseyoidea and transferred to the superfamily Striarioidea. The species is known only from four counties in Washington State in the North Cascades: Pierce, King, Thurston and Whatcom. The occurrence of U. bumpusi from Whatcom County is a significant range extension.

Cryptic diversity in Andrognathuscorticarius Cope, 1869 and description of a new Andrognathus species from New Mexico (Diplopoda, Platydesmida, Andrognathidae).

Andrognathus is a genus of small, thin-bodied millipedes found in deciduous forests of North America. Poorly understood, these organisms inhabit decaying wood and have morphologically conserved and difficult-to-identify sexual characters that have limited study historically. Recent use of scanning electron microscopy has uncovered variation in male genitalia that was previously unknown in the genus. The distribution of Andrognathus and the extent of this variability across the continent, however, were undocumented, and a wealth of natural history collections remained uncatalogued. Here a new species of Andrognathus is described from New Mexico, Andrognathusgrubbsi sp. n., natural history collections are utilized to create a comprehensive map of the genus, and a neotype established for the type species, Andrognathuscorticarius Cope, 1869. Analysis of the cytochrome oxidase I gene (COI) for A.corticarius was completed for the type series and individuals across the species distribution, but little variation was found. Andrognathusgrubbsi sp. n. joins A.corticarius and A.hoffmani Shear & Marek, 2009 as the only members of the genus.